In wind turbines a hub is normally driven in a rotational manner due to the wind affecting a set of blades attached to the hub. This rotational movement is transferred to a generator via a drive train arranged inside a nacelle arranged on top of a tower construction. The drive train normally comprises a gear arrangement which increases the rotational speed of the hub to a speed which is suitable as an input for the generator. In some cases the drive train comprises a main shaft which transfers rotational movement from the hub to an input shaft of the gear arrangement. Such a main shaft is normally supported by a main bearing arrangement comprising one or more bearings, the main bearing arrangement being connected to a support structure of the wind turbine. The main bearing arrangement allows the main shaft to rotate relative to the support structure.
EP 1 457 673 discloses a drive train for a wind turbine comprising a hub, a rotor shaft, a main bearing, in the form of a locating bearing, and a shrinking washer, where axial forces of the rotor are absorbed in the main bearing of the rotor shaft. The main bearing comprises an outer raceway which is connected to a support structure, such as a base frame of a nacelle, of the wind turbine at bottom and top parts of the support structure. Thus, axial forces are transferred to the support structure via a connection between the outer raceway of the main bearing and the support structure, the connection being arranged substantially parallel to a rotational axis defined by the main shaft.